Volatile fission-product diffusion in reactor-fuel matrices

Background

The diffusion of gaseous fission products such as Xe and Kr in nuclear fuel constitute significant performance and safety parameters for reactor operation. The study of diffusion behaviour in nuclear fuels is an experimental challenge however, both due to difficulties in adding gas species to the fuel matrix and in accessing techniques which can and monitor gas concentrations at low-length scales. The majority of diffusion parameters used for UO2 fuel performance analysis, have been derived either: from irradiated material measured in the plenum; or by gas release from the annealing of fuel samples. These methods suffer from the fact that bulk- and grain-boundary thermal and athermal diffusion, as well as radial and axial temperature-variation in the fuel, are highly approximated.

Project goal and work plan

The goal of this project, is to study the thermal-induced diffusion of volatile elements in heavy sample matrices, by medium-energy ion implantation followed by ToF-ERDA (time-of-flight elastic recoil detection analysis). Elemental depth-profiles of the samples are obtained, both as-implanted and post-annealed. The project can be divided into the following key tasks:

• implantation of volatile elements in a range of heavy sample matrices, using the ion-implanter at the Tandem laboratory;
• assessment of the implantations with ToF-ERDA, using the 5 MeV accelerator at the Tandem Laboratory;
• perform sample annealing at a range of temperatures and temperature gradients;
• repeat ToF-ERDA measurements to evaluate the thermally-induced diffusion of the implanted ions;
• write a report summarizing the results and conclusion of the work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a physics program at Uppsala University and possess:

• good practical abilities
• a strong interest in experimental work;
• excellent skills in both written and spoken English;
• knowledge/training in Nuclear Physics will be advantageous.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

For further information please contact:

Robert Frost rob.frost@physics.uu.se